The following documents disclose continuous processes for producing peroxyacids or the like from hydrogen peroxide, sulfuric acid, and a carboxylic acid: U.S. Pat. No. 2,816,147, issued to Weber et al. on Dec. 10, 1957; U.S. Pat. No. 3,140,312, issued to Kurhagec et al. on July 7, 1964; U.S. Pat. No. 4,087,455, issued to Prescher et al. on May 2, 1978; Canadian Pat. No. 744,391, issued to Wenzke et al. on Oct. 11, 1966; and U.S. Ser. No. 895,411, filed by Camden et al. on Apr. 11, 1978 (the latter application is owned by the owners of the present application).
The Wenzke reference is distinguishable because it teaches the production of lower aliphatic peroxyacids which are removed from the reaction vessel by distillation, while in the present invention the peroxyacid must be solid in order to be removed by filtering, as will be disclosed in more detail hereinafter. The Weber reference provides for separate cooling of two reactant streams before mixing them in the reactor but does not allow for any predilution of the reactants with reactor contents. The Kurhagec reference alleges a continuous process for producing peroxyacids, but the specification of that reference does not teach how to adapt the disclosed batch processes to continuous operation. The Camden case includes a brief description of the present invention which was inserted as a description of the best mode of practicing that invention, but the disclosure embodied therein is the invention of the present inventors and is not seen to be prevented by any statutory bar from being claimed in the present application.
The Prescher reference teaches that a peroxyacid product may be removed from the reaction mixture by extracting reactor effluent with an organic solvent, followed by the steps of mixing the resulting raffinate with fresh peroxide solution, distilling the raffinate to remove water, and reinserting the raffinate into the reactor. The Prescher reference is distinguishable from the present invention in several respects, including the requirements in Prescher of a separate distilling step to remove water from the reaction mixture and the apparent need in Prescher to remove the peroxyacid from an organic solvent in which it would necessarily be dissolved in the process of performing the required solvent extraction. The Prescher process also does not provide for the predilution of reactants with reactor contents in order that the heat of dilution of the reactants may be largely dissipated before the reactants are introduced into the reactor.
Numerous prior art references indicate the problem in the prior art of performing the present reaction safely, since if the reaction is not carefully controlled it can become uncontrollable, resulting in an exothermic reaction or even an explosion, or at least in an obstruction of the passages of the reaction apparatus.